This invention relates to the treatment and prevention of viral infections in plants. More particularly, it relates to the use of animal interferons as agents for the treatment of viral infections in plants.
Viral infections in plants represent a severe problem in agriculture. Citrus crops, tobacco and potatoes are examples of important crops which can be severely damaged by viral infections. Not only can plants be infected in the field, but also viral infection can be passed on from one generation to the next as plants are propagated. The problem of viral infection in potatoes is so pervasive that great effort and sums of money must continually be expended to raise virus-free "germ stock". This germ stock must be grown in a geographical area which is known to be relatively free of vectors (e.g., insects) which transmit potato viruses. Moreover, the germ stock must be grown under scrupulously controlled conditions to assure that it is not exposed to infection. Even when these precautions have been taken, however, there is no certainty that the germ stock will be totally virus free. Once the virus-free germ stock is exported and used as seed in an area where viral transmission is prevalent, the resulting potato crop cannot thereafter be used to seed the next season's crop because of the likelihood of infection in the field. Rather, the farmer must purchase new virus-free stock to seed his crop each year.
An effective means of treating viral infections in plants and/or an efficient means of producing virus-free germ stock would be of considerable value in agriculture.
It is known that the cells of plants respond to viral infection by producing a substance (believed to be proteinaceous) which confers a degree of immunity to viral infection upon surrounding uninfected cells (Sela, Biochemical Sciences, Feburary 1981, pp. 31-33). This substance has been given the name "antiviral factor" or "AVF". However, AVF has not been purified to homogeneity, nor has its chemical structure been elucidated.